Automatic telephone system



Oct.y 14, 1941.

J. KuczHLJsYv ETAL AUTOMATIC TELEPHONE SYSTEM Filed Dec. '17, 1938sheets-sheet 1 J. KUCHLEY ET AL AUTOMATIC TELEHONE SYSTEM oct. 14,1941..

4 sheets-sheet 2 Filed Dec. 17, 1938 y c NSN J.

J ww zw 5.9.... m vh `v w my 4 m mu a o waw EN NSQN m mm m I gil K .SQ@www mx m .u NSEM @am wm Z T ull @QN Nnw Oct. 14, 1941. J, KUCHLEY ErAL2,258,854

AUTOMATIC TELEPHONE SYSTEM Filed Deb. 17, 195s 4 sheets-sheet a FIG.5

INVENTORS Jau-'F /fl/CHL fr ATTORNEY.' l

Oct. 14, 1941. l J, KUCHLEY ET AL 2,258,854

AUTOMATIC TELEPHONE SYS TEM ATTORNEY.

Patented ct. 14, 194i AUToMATio TELEPHONE SYSTEM Josef Kuchley,Berlin-Siemensstadt, and Walter Pinell, Falkensee, near Berlin, Germany,assignors to Fides Gesellschaft fr die Verwaltung und Verwertung vonGewerblichen Schutzrechten m. b. H., Berlin, Germany Y ApplicationDecember 17, 1938, Serial No. 246,336

In Germany December 23, 1937 16 Claims.

In distance communication, in particular telephone systems, it is knownthat connections in a remote exchange extend over connecting paths forthe trafc having junction lines which are connected to the exchange setof the calling sub: scriber. This arrangement can be uneconomic When thetraflic in the remote exchange sets require special auxiliary devices,for example, for the purpose of sending out impulses, supervising, etc.,since in such cases all the connecting paths for the internal trailicmust be provided with these. With a large concentration of traffic inextraneous exchange sets a large number of connecting paths must beprovided especially when the principal trafc peaks or internal andconnected traffic coincide.

Connections in remote exchanges can be passed over connecting lines forthe internal tralc within the exchange sets of the calling subscriberwhile the connections themselves extend over special connecting paths.By this arrangement after seizing of the connecting path for internalconnections for the calling set the desired remote exchange set ischaracterized Whether by selection of a characterizing digit or by theexecution of a particular switching measure (pressing ofthe key) andthereby connected with a free junction line over the associated selectorin the desired direction which is connected with the calling junctionline. The connecting path seized by the call is thus freed for internaltrahie. This arrangement has the advantage that the connecting pathserving for the internal trafic need not be provided with the deviceswhich are necessary solely for the traii'ic in the extraneous exchangesets. The number is further not increased or only increased to aninsignificant amount compared with the number necessary for dealing withinternal traic.

If selectors with multiplied contacts are associated with the junctionlines to the exchange sets the connection of the junction lines to thecalling junction line requires a certain period of time during which thecalling subscriber cannot send out impulses for setting the selector inthe remote exchange set. He must await the connection or disappearanceof an exchange signal from which he recognizes that impulse receiversare now ready to receive the impulses. This arrangement is speciallydisadvantageous in the characterizing of the remote exchange set by theselection of a characterizing circuit. Storage devices can now beprovided which receive the impulses so that the calling subscriber neednot desystems having selectors which are directlyset on the calling setit is not desired to provide such auxiliary devices.

The present invention shows a way in which at the same 4time specialinstructions for the subscriber (wait until an exchange signal is heardor disappearance) on the initiation of a connection from an extraneousexchange after seizingV of a junction line to external connections by acall and further storage or the provision of in-v ternal junction lineswith devices for fuliilling special requirements for junction traiiic(e. g. the signalling devices) are avoided. 'Ihe invention attains thisresult in that the outgoing junction lines to the extraneous exchangesets are provided with special access which is obtained over theinternal connecting path seized after the characterizing of the remoteexchange, and vover which dial impulses for setting the selectors in theextraneous exchange can be sent out previous to the connection of ajunction line to the calling exchange line resulting when the connectionpath is switched over.

By means of the arrangement according to the invention the callingsubscriber has the possibility of sending out impulses for setting theimpulse receiver in the desired exchange directly after characterizationof the desired exchange in a particular manner (selection ofcharacterizing digits or pressing of a key). The use of the connectingdevices serving for internal traic continues only until the connectionof the junction line to the calling junction line of a special selectorserving merely for the junction traflic.

A further advantage of the arrangement according to the invention isthat large group selectors can be used for traiiic with the remoteexchange without an especially high operating velocity or speciallyconstructed testing devices or storage devices being necessary, whilethe subscriber need not delay the sending out of impulses.

A special access to the junction line can be obtained over an impulsereceiver for internal connections but also over another station of theinternal connecting path seized by the call e. g. following a selectingstage.

According to the invention the special access of the junction line canbe metallically connected with the speaking conductors of the internalconnecting path. It is then possible 'whenthe junction line to theremote exchange cannot be made over the connecting selector e. g. as aresult of lay sending of dial impulses. Especially with disturbances, toby-pass the speech traine over the internal connecting path by thespecial means of access.

According to another feature of the invention the present switchingmeans are provided which when a desired line becomes disengaged preventthe switching back of the call to an engaged subscriber having callstorage facilities, but cause the call to be switched back when thesubscriber who has stored the call becomes free. The switching back ofthe call to the waiting subscriber only results then when the requiredline and the waiting subscriber who has stored the call are both free.

This has the advantage that the waiting subscriber only has the calledline at his disposal when he himself is also free. The subscriber inanother conversation is thus not disturbed. The

required line can be placed at the disposal of a further subscriber inthe interval in which the waiting subscriber is engaged in anotherconversation.

In arrangements with call storage when a called line is engaged and thestorage of the call is maintained through further outgoing and incomingconnections the subscriber does not need to undertake the selection ofthe desired line again after receiving the automatic switching back ofthe call when the desired line becomes free. He is connected inpreparation to the called party by means of the call storing operationsof the selector which has operated previously.

In order that the subscriber'shall determine whether the selection ofthe required line shall take place immediately or only after switchingback further features are provided according to the invention which areassociated with the called line and decide whether the required line isto be reached immediately or after the call has been stored. Theselection of the desired line can then take place independently ofwhether the call is stored or whether the desired line is immediatelyfree. The subscriber also has to perform the necessary switchingmeasures after selecting the desired line again after the switching backof the call. For example, he has to select the characteristic digits ofa required line in each case even after call storage before theselection of the digits of the required subscriber is undertaken. Ifafter the switching back of the call no further digit selection takesplace the subscriber receives the engaged signal.

In the drawings systems are shown as embodiments in which the selectorsserving the tralc to the extraneous exchange are associated with theoutgoing junction line. It is understood that the invention can also beused for the purpose of connecting traffic, the junction lines beingprovided with a special discriminating selector for junction traffic.

Figs. 1 and la relate to a circuit for a fully automatic rural exchangewith local and main exchanges and characterizing digit selection andcall storage.

Fig. 2 shows an arrangement in which in contrast to Fig. 1 on seizing ofa free connecting line VL the other connecting lines are not` guarded.

Figs. 3 and 4 show further embodiments for impulse receivers serving tosend out impulses over internal routes.

In Figs. 5, 6 and 7 various possibilities for sending out impulses tothe junction lines having directive selection by the pressing of a keyare represented.A

Only the details necessary for understanding the invention arerepresented and described. Thus in the gures a local group AS, L-W and aline VL and a remote group AS only are shown.

Internal routes extend over selectors OAS-OLW and the incoming exchangetrailc over FAS and FLW in the usual way. For the purpose of theinvention only the outgoing cxchange traillc is of interest.

In Fig. 1 initiating of an outgoing exchange connection to anotherexchange takes place as follows:

When the subscriber N lifts up his receiver thc subscribers relay Roperates over contact It, subscribers loop, contact 2t, winding I ofrelay R, battery, By means of a Contact 31- the seizing circuit for theselector OAS is closed over contact lit. The relay RA operates overcontact |211 and by means of its contact Era completes a circuit forrelay Q, winding I, over contacts 6c and 1v. Over contact Bq the rotarymagnet AS is connected. The selector OAS rotates its wiper in alternateplay between the relay Q and contact Sas until the relay C tests on thesubscribers connection characterized by means of the contact l8r overthe c-Wiper of the selector OAS over the following path: earth, contactHra, windings I and II of relay C, c-wiper of selector OAS, contact |81,winding II of relay R, operated contact IMT winding I of relay T,battery. Relay C operates and stops the selector at contact 6c andswitches through the talking conductors over contact |80 and |90. Overcontacts |3c and |4o| relay C holds, short-circuits its winding II andguards the nder switch against further seizure. Over the contact |50 therelay V operates, and over contact |611 the d-conductor of selector OASprepares a circuit for the relay F associated with thesubscriber.Contact 'lv causes the relay Q to restore again.

Over contact HUI in its normal position, upper windingv of the repeater,a-conductor, operated contact-|80, a-wiper of the selector OAS,subscribers set, b-conductor, b-wiper of the selector OAS, operatedcontact |90, lower winding of the repeater, contact 200|, and earth, therelay A operates. Contact 2|a operates the relay J and contact 227' therelay V|'. Relay VI holds during the sending out of impulses. Relay Aholds over operated contact |'lv|, relay J holds over earthen the chokecoil Dr after the operation of Contact 200|. Over contact 23a andoff-normal contact 24u) of the selector OLW the subscriber receives theexchange signal or dial tone WZ.

It will be assumed that the subscriber who wishes to make a local orremote call, will select the digit Or for this purpose. By theinterruption of the loop the relay J restores. Over contacts 37:1' and3Ec| relay V2 operates and during the impulse transmission this relayholds and shortcircuits the choke Dr by means of its contact 21122. Overthe operated contact 2812!, contact 247' in its normal position, contact25u and offnormal contact 26u; of OLW, the vertical magnet H of theselector OLW operates. The wipers of the selector OLW are now raised bya number of steps corresponding to the numberlof interruptions in theloop.

After the switch has been stepped up, i. e., in

the case assumed, after it has reached the setting epesses-lrotary'magnet D of the selector OLW is operated. The rotary oil-normalcontact 34d of the selector OLW energizes the relay U and the relay Uinterrupts the circuit for the rotary magnet D at contact 32u. Thisalternate control causes the rotary magnet D to rotate the wipers ofselector OLW over the bank contacts to hunt for a free junction line.Relay P testover the c-Wip'er of the selector OLW, contacts 35u, 38112,36a and 29k to the battery potential on the cconductor.

Junction Zine free It will rst be assumed that a connecting line, forexample selector FAS, is free and the contact 48g is in the normalposition. The relayv G, which is common to all selectors FAS, operateswhen one selector FAS is seized and guards all the remaining junctionlines by operating all the contacts corresponding to 40g until selectorFAS has been set on the subscribers junction line.

In this way cross connections to a subscribers junction line by thesimultaneous testing of several selectors FAS is avoided.

The relay P of the selector OLW operates over: battery, off-normalcontact 39M of FLW, contact 130g, winding of relay CI, contact M2171,and cconductor. By means of contact 42p the winding I of relay P isshort-circuited and the line on which the selector OLW is tested isguarded. Over contact 33p the magnet D is disconnected and the selectorOLW is stopped. Over contacts 43p and Mp the talking conductors of theselector OLW are switched through. Over contacts 45p and 46g earth isconnected to the z-wiper of the selector OAS over the conductor Bes,

and thus the subscribed N is characterized by a multiple connections tothe selector FAS.

4By means of the short-circuiting of winding I oi relay P the relay CIassociated with the connecting line VL operates and holds independentlyof contact 40g over its contact 410|. Contact 480| energizes the relay Gwhich opens contact 40g. Over contact 560| earth is disconnected fromthe c-conductor of the selector FAS so that vthe relay PI can no longertest. At contact |c| the test circuit of relay Pr is vprepared. Overcontact 52e! the starting relay An of the selector FAS operates and overcontacts 53am, 55m and 56m the rotary magnet DFAS operates and rotatesthe selector FAS under con-l Further selection After the selection ofthe characterizing digit the subscriber can immediately begin to dialthenext impulse series. He need not delay the im.

pulselsendingntil a connection'gto the junctionj line-VLis V.completedover the selectorfFiiS;

c If the connecting line VL is free, selector OLW has direct access -tothe impulse relay Al, associated with- VL, which is operated over thea.- conductor, OLW, contact j, 43p and 8|q. ContactA 9Ia| brings up therelay V3 which holds during the impulseseries. Contact 92113 cuts offthe relay J serving for incoming traffic from the a-conductor of VL.Contact S'Ial connects battery to the a-conductor of the exchange lineover the coil DTI.

v`-On-tl'ie operating of the dial the relayv J of the local connectionis' restored as well as in the characterizing digit selection and at itscontact gfdisconne'cts earthv from the a-lead over contactslq, 82jv2,43p. InY this way the relay Al in the a-conductor of the junction lineAVL is restored and at contact 91a| removes battery from the a-lead insynchronism 'with the impulses.A On the release of the relay A| relay V4operates over contacts 93113', S4a| and 957| and holds during theimpulse series andthe coil DTI is short-circuited by its contact 96114.

In order to ensure that the impulses are not mutilated the arrangementis such that the switchingthrough of the selector FAS associated withthe connecting line VL is only possible at the end of an impulse train.

For this purpose it is arranged that in dependence on the relay V4which, is operated by an impulse train, an additional relay Tr isinuenced which controls the switching through relay PH.

In Fig. 1 the circuit of the relay Tr is interrupted -by means ofcontact 6h24. At the end of the impulse train thecontact 6h24 isrestored to normal. Meanwhile -therelay Pr of the selector FAS hastested on the subscribers junction line, as described previously, andthe relay Tr operates over contacts Blvd and 62221 and holds over itsown contact 63tr. Contact 6413?' connects earth to the c-wiper of theselector FAS, so that the switching through relay C of the selector OASis short circuited and the internal connecting path is released. Bymeans of contact 65h" the switching through relay PH is energized andeffects the switching through of the talking conductors of the selectorFASr by vmeans ofits contacts v'mph and 1 5ph.'

Over contact 131m earth is connected to the dwiper of theselector FASand is connected to the d-wiper of the line leading to the selector OAS.The relay F which maintains the storage of the impulses isthus shortcrcuited and restores. The impulses are no longer stored. Over contact4|ph and c-conductor tothe selector OLW is interrupted.v Relay C|associated with the connecting line is restored.

Relay H2 which operated over contact '180| holds over contact 19111'.Contact 8'8'h2 closes the a-conductor of the selector FAS and overcontact 89h2 and choke DTZ connects earth to the b-conductor of thejunction line VL. The relay P1' holds over the contacts 58m' and 6|v3which is operated during the impulse transmission.

After the closing of the final connecting path from the connecting VLover the selector FAS to the subscribers connection and release ofthelocal apparatus OAS-OLW, the dial impulses arel transmitted as loopimpulses over earth, choke DrZ, contacts 89712, 83114, '|5ph, b-wiper ofFAS, b-conductonrsubscribers station N, a-conductor, a-.wiper ofFAS-,contact '|4ph, 88h2, reA-M laylAi. Tha-delay in'4 theoperationfofthe switching through i relayl PH .of selector FAS andtherelease period lof'. the switch through relay C of selector IOAS is sovarrangedinviewA of the short-circuiting, that ndimpulse'.` gets lost. In

order tov avoid controlling the .impulse relay' Ai simultaneously at VLover the internalas Well as i' over the final connecting path,v bothAperiods are made substantially the same.

No junction Zine' free If no junction line to the extraneous exchange is.free a subscriber receives the-'engaged signal Bes over contacts 45p,24111, 23a, He can hang up and hold an internal .conversation duringthe` waiting period., His call remains stored over the relay F during.the localconversation of the subscriber. Junction lines which became.free are at the disposal of: other subscribers. j

If several subscribers calls are stored-but: are not engagedinlocal-.conversations and therefore are ready toseize the connection, thesubscriber whose associated selectorrst Yreaches the junction line VLseizes the-connection to the remote exchange.

It will be assumedl that the subscriber N with a stored call is thefirst who is ready to seize the line.

Revertioe calling 'When on the release ofa junction line VL, thesubscriber Nis free andhashungup, the selector FAS associated with thefree connecting line over contacts tilllfV and lll lt'starts up in thatthe relay An operates.

The selector FAS of the junction' line VLtherefore comes under thecontrol of-two call receiving devices in the first placeiunder thecontrol of the seizing relay CI Iwhich' is reached only over theinternalV connecting path with special access to VL, and in the othercase under the influence of relay F storing the call when all connectinglines VL are engaged.

Over contacts 53cm, 55101' and 55p! the -rotary magnet DFAS operates androtates thel selector FAS with the aid of the interrupter UI until-thetest relay PI tests over contacts 50cl and I03an, c-wiper of theselector FAS, contact 12j, winding 'II of relay R, contact' BSt, windingI of relay T. The contact 50cl is in its normal position when thecorrespondingv junction` lineA is free.

By testing on the call of the subscriber `N stored over the contact .12jrelay Pi operates and again stops the selector FAS over contact 56p!`and. short circuits its Ysecond-winding byr means of contact' |05pl.

Over Vthe operated contact 56p| .theA relay PH operates and switchesthrough the talking conductors of the selector 'FAS over the contactsMph and '151311. Over the contacts? 8111.2 and 89h2and .the windings Iand II of relay RI: the subscriber N receiveszcalling. current, over thetalking conductors. vThe call from the `exchange is convenientlydifIerentiate'dfrom anfinternal call bythe length of the ringingzsignalexchange signal from selector'FAS.

The subscriber can, after lifting up `his receiver, `send out the numberof 'the desired subscriber `corresponding to the characterizing' digitsof the resulting impulse train. Then infknown manner the selector in themain exchange is set corresponding to .thef impulse train andtheconue'ction to the desired subscriber isset up.

'-65 Thel subscriber N after receiving theicalllifts up his receiver andimmediately receives the The arrangement can, however, also becoriveniently such that the' subscriber after the switching backlofthecall has to select the complete'number. of. the vcalled party again, i.e., he must carryout the digitselection again. He need then,A 'notidifferentiate between the selection without callf storage and theselection after call storage. If the: subscriber in the last arrangementdescribed forgets to dial the characterizing digit again, he receivesthe engaged signal.

Further selection according to this arrangement will be described indetail with reference to Figs. 1 and '1a.

The arrangement is such that switch means having access to the junctionline differentiate between the various arrangements for reachingthe'mainzexchange from the junction line, as to whether the connectionextends over internal connecting devices and the special access means(when a connecting line is free), or (after the junction lines have allbeen engaged) directly over selectors serving only the connecting trafoto the remote exchange.

In the selection over the internal connecting path to the otherexchanges the dial impulses are transmitted freely by means of theswitch means affecting the differentiation, while by theselectionldirectly over the selector of the junction line the impulsesare freely transmitted only on the selection of the characterizingdigit. The testing occurring on the selection of the characterizingdigit is performed by a discriminator which by means' of the switchmeans carrying out vthe differentiation on the selection is broughtdirectly under the control of the dial impulses over selectors of thejunction lines. On selection of the characterizing digit switch meansare controlled by means of the discriminator which makes it possible tosend on the impulses to the main exchange. On the selection of digitswhich do not correspond to the characterizing digit the impulsetransmission to the main exchange is prevented, however, and the callingsubscriber receives the engaged signal.

It will be assumed that the number of the desired subscriber at the mainexchange is O 365. The calling subscriber in the sub-exchange then must'always select this subscribers number whether the connecting line ofthe remote exchange is free or is first engaged.

Connecting Zine free If the connecting line is free on the settingup ofthe connection to Athe main exchange over the internal connecting paththe calling subscriber receives the exchange signal after the digitselection, as described, over the internal connecting path. On theselection of the following characterizing digit 3 then, as alreadydescribed, the relay Al of the access means to the junction line iscontrolled in synchronism with the impulses and the impulses aretransmitted over contact Slal. Over contacts 96114, Q'lal and 26502relay A2, (Fig. la) is controlled in synchronism with the impulses. Onethe energization of the relay A2 the relay V5 operates over contact20Ba2 and holds during an impulse train.

On the seizing of the junction line to the remote exchange over thespecial access means relay C! was energized and operated the relay DIover contact 2000i. Over resistance Wi, the operated contact 20ldl, andcontact 202a| which is set back to its normal position by each impulse,battery is connected to the b-conductor of the connecting `line to themain exchange whereby over contacts 203c2 and 204h3 which are in theirnormal positions, relay S is operated. Over contacts 201125 and 208s therelay U2 is operated. Over contacts 209u2 and 2I0125 the impulsetransmission to the group selector GW in the main exchange is madepossible. By the controll of contact 2I|a2 positive .potential isconnected to the a-conductor to the main exchange and the groupselector, which is not shown, is stepped up to the third bank after thedigit has been selected. Over contact 2|2u2 the rotary magnet DM of thediscriminator is disconnected andthe setting of the discriminator isprevented. ,Relay U2 holds over its own contact 2|3u3 and contact201125. The discriminator DM is therefore not operated in this case.

Junction lines all engaged at rst,

Recertvzve calling If all junction lines are engaged the callingsubscriber receives the engaged signal from the local connecting pathafter selecting the characterizing digit 0. He hangs up. His trunk callis stored. The subscriber is free for local traiiic. If in the meanwhilea junction line to another exchange becomes free and in addition thecalling subscriber is free, as described, the revertive call is madeautomatically over the selector FAS of the junction line whereby thecalling subscriber is switched through to the main exchange. Thesubscriber lifts up his receiver and receives the revertive callsignals. The relay Rl of the junction line VL operates and connects therelay H2 (Fig. l) with contacts 22,014 and 22ml. By the operation of thecontacts 88h2 and 8911.2 the relay Rl is disconnected from theconductors a, b of the junction line VL.

'I'he subscriber must now select the number of the subscriber 0.365again. After the transmission of impulses the relay Al of the junctionline VL which is operated by the operation of the contacts 88h2 and89722 restores in synchronism. with the impulses. Relay V3 holds in themanner described over contact Slal and the relay V4 over contacts 93123,94a! and 9571. The impulses are transmitted in the manner alreadydescribed over the contact 91a! to the relay A2 (Fig. 1A). On therelease of the relay A2 the relay V5 operates over contact 206er?. inthe manner already described and holds during an impulse series. RelayU2 does not operate. The rotary magnet DM of the discriminator istherefore controlled in synchronism with the impulses over contacts206112, 220125, 22|el and H2112 i. e. on the selection of the digit 0 itis brought into the position O.

In the position O the relay U2 operates over contact 201125 and wiper208dm of the discrimi nator. Over contact 2l2u2 the rotary magnet DM ofthe discriminator is disconnected. Over contact 2I5125 the relays H3operates and connects earth on the c-conductor of the group selector GWin the main exchange, by means of its contact 21th.?. Contact 209112which `previously prevented transmission of impulses to the groupselector GW is closed. Over contacts 209112, H0115 and 2 l |112 impulsesfollowing on the' digit characterization are transmitted to the groupselector GW in the main exchange. The group selector GW is stepped on tothe third contact bank as previously corresponding to the selection ofthe digit 3.

If the subscriber instead of selecting the complete subscribers number 0365 only selects the digits 365 after Vreceiving the reverted call hereceives the engaged signal.. The transmission 0f impulses to themain'exchange is prevented.

I'nrorderA to obtain this resultthe relay U2 effecting the impulsetransmission is not operated if the discriminator is not set in itsposition O.

On the selection of the digit 3, after receiving the revertive call, therotary magnet DM of the discriminator as described, is controlledv overcontacts 206112, 220125, 22|a| and 2|2u2 and brings the wiper 208dm intopositionV 3 correspondingto the digit 3. In the positions 1 -9 lowerdown than the position O of the-wiper 20801111' the relay ZI operatesover contact 201125 and wiper 20812111 vand locks up over contact 2|1zl.Contact 22|zl'interrupts the circuit for the rotary magnet DM. The relayU2 cannot operate as in the digit selection. Y The impulse transmissionto the group selector GW isi prevented by means ofA the contact 209112'.in its normalposition. The calling subscriber receives the engagedsignal over windings II' of therelays S and'AZA and wiper 2|9dm. L

In'this way the calling subscriber is compelled to select the completenumber of the desired subscriber.'l Y 5 In the embodiment shown in Fig.1 on the seizing of a junction-line (VL) overa iinal selector OLW oftheinternal connecting path by means of the operating relay Cl the blockingrelayv G common to all junction lines, is energiz'ed, and asdescribedybyope'ning theconta'ct corresponding tov the contact 40gin'the access means to the other junction line VL'prevents a furtherjunction line from being seized until the selector FAS of the seizedjunction line has reached the line of the calling subscriber N. vvThe'arrangement can also besuch, however, (Fig. 2') that after the; seizingof an' internal junction' line over connecting paths of theinternaltraic, thelseizing of another `free junction line is notprevented but so long as the 'free june; tion lines canstill be'reachecLall the ifreejunction lines canV be seized over connecting'paths forinternal-traiiicQbut the connecting devices can never hunt'for differentconnecting lines atthe same time as thg'e'callingline. y Y

For this purpose the arrangement according to Fig. 1 is provided with anauxiliary connecting path.v Two auxiliary selectors are providedof'which' one sets itself. Vonthat local connecting path overwhich aconnecting line h'as been seized' and a second auxiliary selector setsitself on the seized junction line.' The setting of these two auxiliaryselectors can be made dependent in known manner onl the closing of anindividual testing circuit which is only completed 'when over connectingdevices ofthe connecting path for internal trailic, taken into use overthe two auxiliary selectors and the Seized junction line, a circuitcontaininga particular current source is completed. Furthermore. a testcircuit for the selector oi the seized junction line is extended overthe auxiliary connecting path and over ini ternal connecting `devicestaken' into use, and

test potential is connected to the test Wiper of the selector of thejunction line as Well as tothe internal connecting path used` bymeans'ofthe auxiliary selector. It is convenient to set the rotary magnets ofthese two auxiliary selectors over a further wiper.

v In Fig. 2 it is shown diagrammatically how the testingAcan beperformedwith the aid of two auxiliary selectors Wl and W2 withoutA all ofthejunction lines being blocked when a junction line is seized over theinternalA connecting `path and several junction lines are free.

When the selector OLW tests on a free junction line VL relay Passociated lwith the selector OLW operates and, over the. contact Ic;operated by the seizing 'of a selector OAS, contact 2160 of the selectorOLW'operated when the selector steps up to the tenth contact bank,contacts lllp and Uhr the relay An. .Operates and over con-- tacts |3an,|6p| operates the rotary magnet DWI of the auxiliary selector Wl over aninterrupter U. Contact 3p short circuits a winding vof the relay P andbrings the` relay Cl of the special access means ZL tothe junction lineVL. When the auxiliary selector W| 'tests on positive potential overthecontacts Ic, A27m, lpyand winding of the relay vI-Ir, relay PI of theauxiliary selector operates Yand over contact |6p| disconnects therotary'magnet DWL The auxiliary selector Wl is stopped.

Over contactslHpL 22e., |8pw the auxiliary selector W2 is rotatedoverrits rotary magnets DW2 and the interruptor U until in the circuit:c-wiper of the auxiliaryselector W|,dwiper of the selector OLW, contact|5c|, c-Wiper of the auxiliary selector W2, contact 4e and alternatingcurrent repeater Tr, the relay PW is operated. Over contact lpw therotaryqmagnet DW2 is disconnected and the auxiliary e selectorWZ isstopped on the position :characterized by means oficontact |5cl. Overcontact |9pw the relay E operates and holds over contacts 20p| and 2|e.Contact 4e interrupts the lalternating currenttestcircuitand contact,22e,'the circuit for the rotary magnet-DW2.. Contact 23e' connects therotary magnetV DFAS of the selectorFAS to the .junctionflineVllover;thed-.wipenof` the auxiliary selectOrrWZ' and contactV 23e.,Over-contacts .24e Vand A25el test potentials are connectedtontheswipersa' of` theauxiliary selector W; W2'. FASoperates -until thefollowing testY circuit is completed for therelay Pr: negative, contact24e, z-wiper `of the auxiliary selector W2, relay Pr, zwiperoftheselector FAS, e-wiperjof theselector OAS,-e-wiper of theAauxiliaryselectorWl, `coni tact 25e, positive. Over contact 26111' themagnet DFAS is disconnected." The connection between the-junction lineVL andthe subscribers line is set up.A

The "impulse transmission overthe internal connecting devices and thespecial access means ZL (Figfl) extending to a junction line VL canalsoibe arranged according to Figs. 3 and 4.

Fig; 3 relates to theimpulsetransmission of an internal group selectorand a bridge relay as an impulse-repeater lin the special access meansto the junction line VL. Inthis case after the testing operation,'e. g.of the group selector OGW the contacts Ip and 2pareoperated, the bridgerelay A disconnected, -and` over' Contact 40| vthe impulsesaretransmitted `to the relay AI of the junction line by meansofftherelay A2 and contact-3a2.

In-Fig'. 4 is representedthe disconnection of the bridge' relay A on:the seizing of the junction line over a` lineV selector OLW andmetallic switching through over' special access means to thejunctiomline. When the-relay P tests over .the c-wiper` of. the selectorOLW on to the relay CI of the junction-line VL which in contrast to therelay of the subscribers line,-is of a 4low resistance, the relay P|operates and disconnects the bridge relayAby means of its contacts' Ipl,2pl, 311|- and 422| and sWitchesthrough the talking conductors a, b.

The loop interruptions on the dial impulse transmissions can betransmitted in Figs. 3 and 4 directly to the relay Al of the junctionline VL after the switching through. This case is shown in Fig. 4.

The loop interruptions can, however, be transmitted to a bridgerelay A2of the special access means of the selector OLW and OGW as shown in Fig.3. Contact 3a2 closes the circuit for the relay AI of the junction lineprepared by means of the contact 40|. In the second case no metallicswitching through of the internal connecting path to the free junctionline takes place. No talking can occur over the outgoing line.

In Figs. lit is assumed that connecting devices in particular dialimpulse receivers of the internal connecting path hunt freely for accessto a free junction line. A free junction line can, however, be huntedfor over a special auxiliary selector in particular when junction linesin another exchange cannot be set up over internal dial impulsereceivers with free hunting. The selector OLW is then set on aparticular contact by means of a charactem'zing digit. The auxiliaryselector with free hunting which is arranged further on is eitherstarted by the characterizing digit selection or it is preset. A

In Figs. 5, 6, 7 circuit arrangements are shown in which the connectionsto another exchange are set up over points which have access to internalconnecting devices in particular to dial impulse receivers and to aspecial access means to a junction line in another exchange. Over thepoints, impulses can be transmitted to another exchange until aconnection is set up between the seized connecting line extending to theother exchange and the subscribers line. The switching operation resultsconvenientlyby the pressing of the key at the subscribers station. Inorder to hunt for a free junction line an auxiliary selector HW is usedwhich either operates by means of pre-setting (see Fig. 5) so that whena junction line is free indirect impulses can be transmitted to thejunction line connected to the other exchange, or the auxiliary selectoris only started up after the operation of the points (see Figs. 6 7).The arrangement according to the preceding figures can be suchthat overthe points a metallic connection to the special access means inthejunction line is set up (Figs. 5 and '7)'. The arrangement, however,can be such Athat over the internal connecting .path only dial impulsesfor setting dial impulse repeaters can be transmitted to the otherexchange without a talking connection being setup. (see Fig. 6).

In Fig. 5 after the selector OAS has been stepped up and has tested onthe subscribers line in known manner the relay C is energized (notshown).` By the pressing of the key at the subscribers stationA for`setting `up a connection to another. exchange theV relay X is energized,and by means of its Contact |23:` energizes the relay E over the rotaryoil-normal contact Slclw of the selector OLW. The point contacts |e and2e aret'opel'ated. Relay E'hclds over contacts Me and llo independentlyof the pressing of the key. Aiurther contact, not shown, of the relay Einterrupts the setting circuit of the selector OLW so-that this can nolonger be iniluenced by the impulses which follow.

The auxiliaryy selectorIIW is provided with a pre-setting arrangementand when a junction line is free it sets itself on this free junctionline. The auxiliary selector HW is rotated until the operation of' itstest relay Pl over contact 20m,

rotary magnet DHW and interrupt'er U2, when the test relay PI operatesby testing on a resistance Wi associated with a free junction line VL.It is arranged that one winding of the test relay is only shortcircuited when the access means ZL to the junction line VL is seized bythe operation of the relay E. By the operation of the relay E the secondwinding of the Nrelay PI is short circuited over contacts 2| pl and 22e.This has the consequence that the other auxiliary selectors whose testrelays are also operated over their d-wipers and the resistance Wi andare stopped on the same contact, again restore since by theshort-circuiting of one'winding of the relay Pl over contacts 2 I pl and22e they are disconnected. The remaining auxiliary selectors are,therefore, connected again to the interrupter and stepped on to the nextfree junctio-nline. After the operation of the relay Pl the magnet DHWof the auxiliary selector is disconnected over contact Zpl. 'Ihecontacts 3011i and 3lpl switchthrough the talking conductors aand b.Over contacts 32pl, 33e, wiper c of the auxiliary selector HW, relay Clof the junction line operates.

If the auxiliary selector is not pre-set on ak free junction line, it isstarted in dependence on the operation of the points ,whichv in thepresent case is done by relay E. Fig. 6 represents this arrangement.When this is used the rotary magnet DHW of the auxiliary'selector isenergized over the interrupter U3 until therelayPl tests on a freejunction line (relay C) .over contact 54e and d-wiper of the auxiliaryselector HW. The contact 5710i disconnects the rotary magnet DHW.Contacts 55p| short-circuits a winding of the relay Pl. The contactsEZpI and 53p| switch through the conductors a and b'of the auxiliaryselector HW.

The impulse transmission to the relay Al of the junction line VL takesplace in Fig. 5 Vover contact 35a of the relay A of the internalconnecting path. During the impulse transmission the relay Vl holds andthe relay V2 operates over contacts llvl and 9a. Relay V2 holds duringan impulse train.

In Fig. 6 the impulses .are transmitted over contact Ela after thecontact 50cl has been closed. Relay Al of the junction line is restoredin synchronism with the loop interruption and as in Fig. 1 transmits theimpulses over the junction line.

The initiating ci" a connection from theseized junction line to thesubscribers line by vlay-passing the local connecting path (OAS) cantake place in Figs. 5 and 7 directly after the direction selector e. g.by means of the relay E, or by seizing of the junction line (VL, relayCl) as shown in Fig. l. After the icy-passing of the local connectingpath the impulse transmission as in Fig. l follows directly over theselector FAS.

In Fig. 7 a further embodiment is shown for Fby-passing by means ofpoints and selection of a free junction over'an auxiliary selector. Theimpulses are here transmitted to the relay AI of the junction line VLdirectly without using internal impulse repeaters. After the pressing ofthe key and operation of the relay X the relay Xl is operated overcontacts like and 9c. On release of the key, i e. the release of relayX, the switching relay E is operated over contacts 8x and i212! andholds over contact |30 and lite. Over contacts x and 2010i the rotarymagnet DHW is energized over the interrupter Ud. VThe operating circuitis maintained after the release of relay X over contact I Bxl and afterthe disconnection of the relay Xl over contact lle.

. When the auxiliary selector HW tests on relay CI associated with afree junction line VL relay PI operates, and disconnects the rotarymagnet DHW at contact 20p! and stops the auxiliary selector HW. Overcontacts 21p! and 22p! the talking conductors of the auxiliary selectorHW are switched through. Contacts 'le and 8e control the access means tothe junction line VL.

The loop interruptions caused by the dialling of the subscriber Ndirectly control the relay Al; associated with the junction line.

What is claimed is:r

1. In a telephone yor'like system,v a first exchange having one or moretrunk lines outgoing to a second exchange, a calling subscribers line inthe rst'exchange, lmeans localto said first exchange controlled oversaid calling line at times to extend a connection from said calling lineto the line `of `another subscriber in the same eX-f change and at othertimeslto extend a'temporary connection from said calling line to one ofsaid trunk lines,a callingdevice at the calling station operated by thesubscriber thereat at said other times to control switching apparatus atthe second exchange over said temporary connection and said trunk line,`and means for .releasing said temporary connection before completion ofthe controlling of said switching apparatus at the second exchange'and,at substantially the same time, substituting another connection for saidtemporary connection, said calling device thereafter controlling the'switching apparatus at said second exchange over said other connectionand said trunk line. i ly 2. In a telephone system, afirst exchangehaving a trunk line extending to a second exchange, subscribers linesterminating 'at the firstv exchange, switching apparatus at the firstex- Y change having access to said trunk line and to said subscriberslines, means for seizing said switching apparatusover a calling one ofsaid subscribers lines and at times controlling same to seize said trunkline, means insaid switching apparatus responsive to impulses receivedover the calling line forcontrolling the transmission of correspondingimpulses -over the trunk line to operate switches in said secondexchange, other switching apparatus in the rst exchange terminating saidtrunk line and operated to connect with the calling line responsive tosaid seizure of the trunk line, means for releasing said rst switchingapparatus rwhen said other switching apparatus Yhas connected ,with thecalling line,

said impulse responsive means in said rst switching apparatus beingdisabled upon said `release thereof, Aand means in said other switching'apparatus vthereafter responsive to impulses received over the callingline for controlling 'the transmission'of corresponding impulses overthe trunk line to' continue the operation of the :switches insa'idsecond exchange. f Y

3. In a telephone system,ia local exchange having trunklines outgoing toa distantexchange', subscribers lines terminatingat the localexchange, alocal switch train for completing connections lbetween said subscriberslines, means for at times controllingxsaid switch train over a callingone of said subscribers lines'to extend a temporary'connection from saidcalling line to a trunk line, means for vsubsequently completing anotherconnection between said calling line and the trunk line and forthereupon releasing said temporary connection, means controlledloversaid temporary'connection from the calling Vstationbefore saidrelease thereof vfor transmitting impulses over said trunk line, saidlast means being controlled over said other connection from the callingline' after .the release of said temporary connection.

4. In a telephone system, a local exchange having trunk lines outgoingto a distantfexchanga subscribers lines terminating atz'the `localexchange, a local switch train for completingv connectionsbetween said`subscribers lines, means for at times controlling said switch ytrainover a calling one of saidsubscribersV lines to extend a temporaryconnection from; said calling line'to a trunk line, said means includinga calling device at the calling station thereafter operated by thesubscriber thereat .to transmit impulses over said temporary connectionand said trunk line to set switches atthe distant exchange, and meansfor releasing said temporary connection` before completion of thesetting of said switches at the distant exchange and, at ,substantiallyvthe same time, substituting another connection for saidtemporaryconnection, the,V impulses from said calling device thereafterbeing transmitted over said other connection and the trunk line` to thedistant exchange.

5. In a telephone system, a local exchange having trunk lines outgoing..to-a distant exchange. subscribers lines terminating. at the localexchange, a local switch .train for completing connections between saidsubscribers lines, means for at times controlling said switch train overa calling one of said subscribers lines to seize one of said trunklines, a finder switch in said local exchange terminating saidtrunksline and voperated to connect `with the, calling linefresponsiveto said seizure of the trunk line, means for releasing said local switchtrain when said nnder has connected with the calling line, Vmeansresponsive to impulses transmitted over said call ing line and saidlocal switch train before said release thereof for transmitting`corresponding impulses over the trunk: line toccontr'ol the lsetting ofswitching apparatus inithe 4distant exchange, said lastmeans beinglresponsive to* impulses transmitted over said. calling line and saidfinder switch vafter Jsaid release `of said `switch train for`transmitting corresponding. impulses over the trunkline to continuecontrolling the setting of the switchinglapparatus in the distantexchange.

6. In a telephone system, a locallexchangelhaving trunk lines outgoingtoa distant exchange, subscribers4 lines terminating vat the localVexchange, a local switch train for completing connections vbetween saidsubscribers lines, said. train includinga numerical switch, meanscontrolled by the initiation of' a call from one of said subscriberslines for extendinga connection from the calling line to said numericalswitch, acalling device at the calling station operated 'at times aftera connection has been extended to said numerical switch to control saidswitch to extend a connection .to awanted subscriberslinefinA the localexchange, other means at the calling station operated at other timesaftera connection has been extended to said numerical switch `to seizeone of said trunk lines without operating -said switch, switchingapparatus in' the ,local exchange terminating said one trunk line andoperated to connect with the calling line responsive to said seizure ofthe trunk line, means for releasing the connection from saidA callingli'neto said numericalV switch when saidswitching zapparatus hasconnected with the calling line, and means controlled bythe callingdevice at the calling station both before said switching apparatus hasconnected with the calling line and after said connection from thecalling line to said numerical switch has been released to control thesetting of ,switching apparatus in the distant exchange.

7. In a telephone system, a local exchange haiing trunk lines outgoingto a distant exchange, a calling subscribers line terminating at thelocal exchange, means at times controlled over said calling line toextend a local connection therefrom to another subscrbers line in thesame exchange, a key at the calling station operated at other times tocontrol said last means to extend a temporary connection to a trunkline, a calling device. at the calling station thereafter operated bythe `subscriber thereat to transmit impulses over said temporaryconnection and said trunk line to set switches at the distant exchange,and means `for releasing said temporary connection before completion ofthe setting of said switches at the distant exchange and, atsubstantially the same time, substituting another connection for f saidtemporary connection, the impulses from said calling device thereafterbeing transmitted over said other connection and the trunk line to thedistant exchange.

8. In a telephone system, a local exchange having trunk lines outgoingto a distant exchange, subscribers lines terminating at the localexchange, a plurality of 'link circuits for completing local callsbetween said subscribers lines, means for controlling one of said linkcircuits over a calling one of said subscribers lines to seize one ofsaid trunk lines, means for controlling another of said link circuitsover another calling one of said subscribers 'lines to seize another ofsaid trunk lines at substantially the same time, switching apparatus inthe local exchange controlled by the seizure of said one trunk line toextend a connection therefrom to said one calling line, other switchingapparatus in the local exchange controlled by the seizure ofsaid othertrunk line to extend a connection therefrom to said other calling line,and means for preventing said rst switching apparatus from extending theconnection from said one trunk line to said other calling line andpreventing said other switching apparatus from extending the connectionfrom said other trunk line to said one calling line.

9. In a telephone system, a first exchange having a trunk line to asecond exchange, means for engaging vsaid trunk 'line for aninter-exchange call, a plurality of calling lines in the rst exchange,means controlled over each calling line toldesignate a call to thesecond exchange, means for storing said calls, means controlled at timesover one of said calling lines while its call is in storage forextending a local call to the line of another subscriber in said firstexchange, a finder switch in said first exchange terminating said trunkline and operated responsive to said trunk line becoming available foranother inter-exchange call to search for and seize one of said callingrlines, and means for preventing said nder switch from seizing said onecalling line while same is engaged in said local call.

10. A telephone system as claimed in claim 9, wherein said last meanscomprises means individual to said one calling line and operated whilesame is engaged in said local call to characterize said one line inthebank of said finder switch.

11. In a telephone system, a rst exchange having trunk lines outgoing toa second exchange,

a calling line in the rst exchange, means in said rst exchange operatedover the calling line to designate a call to the second exchange, meansfor thereupon storing said call if no trunk line to the second exchangeis available, means at times controlled over said calling line Whilesaid call is in storage for completing one or more local calls to thelines of other subscribers in said rst exchange, and means effectiveresponsive to a trunk line becoming available While said call is instorage for connecting that trunk line to said calling line only if saidcalling line is not engaged in a local call.

12. In a telephone system as claimed in claim 11, means responsive tothe designation of a call to the second exchange for seizing a trunkline outgoing thereto substantially at once if one of said trunk linesis available, and discriminating means operated dilerently in dependenceupon whether a trunk line is seized for the call at once or afterbecoming available While said call is in storage.

13. In a telephone system, a rst exchange having trunk lines outgoing toa second exchange, a calling line in the rst exchange, means in saidfirst exchange operated over the calling line to designate a call to thesecond exchange, means for thereupon storing said call if no trunk lineto the second exchange is available, means thereafter responsive to atrunk line becoming available for seizing the calling line andsignalling the subscriber thereover, means at times controlled over saidcalling line While said call is in storage for extending one or morelocal calls to the lines of other subscribers in the first exchange, andmeans for disabling said third means at said times.

14. In a telephone system, a rst exchange having trunk lines outgoing toa second exchange, a calling line in the rst exchange, means in saidfirst exchange operated over the calling line to designate a call to thesecond exchange, means controlled by said designation for seizing atrunk line to said second exchange substantially at once if one isavailable, means for storing the call if no trunk line to the secondexchange is available, means effective responsive to a trunk linesubsequently becoming available while said call is in storage forconnecting that trunk line to the calling line, a calling device at thecalling station operated to control the transmission of impulses overthe trunk line to set switching equipment in the second exchange, andmeans in said second exchange for at times absorbing certain of saidimpulses depending upon Whether the trunk line Was seized substantiallyat once or after becoming available while said call was in storage.

15. In a telephone system, a rst exchange having trunk lines outgoing toa second exchange,

a calling line in the first exchange, means in said first `exchangeoperated over the calling line to designate a call to the secondexchange, means controlled by said designation for seizing a trunk lineto said second exchange substantially at once if one is available, meansfor storing the call if no trunk line to the second exchange isavailable, means eiective responsive to a trunk line substantiallybecoming available While said call is in storage for connecting thattrunk line to the calling line, a calling device at the calling stationoperated to control the transmission of trains of impulses over thetrunk line to operate switching apparatus in the second exchange, andmeans in said second exchange eiective at times in dependence uponwhether the trunk line was seized substantially at once or afterbecoming available While said call was in storage for preventing theoperation of the switching apparatus in the second exchange if apredetermined one of the trains of impulses received over said trunkline does not contain a predetermined number of impulses.

16. In a telephone system according to claim 15, means for absorbingsaid predetermined one train of impulses at times depending upon whetherthe trunk line was seized substantially at once or afterbecomingavailable while said call was in storage.

JOSEPH KUCHLEY. WALTER PINELL.

